Vibrating screen



Mar. 13, 1923. 1,448,1`81

J. J. BABKA vIBATING scREN Filed Oct. 18, 1920 Patented Mar. 13, 1952.3.

tras s rafa a' asics.

VIBRATING SCREEN.

Application filed October 18, 1920.

To aZZ 'whom 'it 'may co'ncem:

Be it known that I, JosEPH J. BABKA, a citizen of the United States ofAmerica, and a resident of Berwyn, county of Cook, and State ofIllinois, have invented certain new and useful Improvements in VibratingScreens, of which the following is a specification.

My invention relates in general to vibrating screens, such as are usedfor screening or grading sand, gravel, ore, crushed rock and the likematerial; and the object of the invention is to provide a novel,inexpensive and highly eificient method of eausing the screen tovibrate, thereby eifecting a'saving in first cost and increasedefliciency in operation.

Numerous types of vibrating screens have been designed before, and someof these prior screens have been fairly successful. S0 far as is known,however, all former screens either do not accomplish the (lesired objecteffec'tively, which is to produce minute high frequency vibrations; orthey do so by means of excessively complicated mechanical or electricalcontrivances which are not only costly to start with, but are whenrotated lat high speed by some suitable' source of power, itwill vibrateat a corresponding frequency. Sincev the shaft bearings are on the frameof the screen the Vi- 0 brations are transmitted to the screen throughthe bearings, and the'screen will vibrate in unison with the shaft.

Having explained in general terms the object and scope of the inventionthe means 5 by which the desired results are accomplished will now bedescribed more in detail, reference being had to the accompanyingdrawing, i-n' which Fig. 1 is a side view of my improved vibratingscreen, while Fig. 2 is a top view of the same.

The screen itself may be of any'approved type. As shown herein itcomprises a rectangular wooden frame about 8 ft. over all in length, and2 ft. width, with an inner' serial' No. 417,768.

frame of square strips on which a Sheet metal or wire mesh screen isstretched and held by staples, cleats or any suitable means. The methodof construction is suificiently ini dicated in the drawing, and since itis well understood by persons familiar with screens, no furtherconsideration will be necessary on this phase of the matter.

The means for supporting the screen will now be explained. The sides 2'and 3 of the frame are attached at opposite ends to the cross pieces 4and 5, which support the weight of the frame. The cross pieces 4 and 5are in turn supported by means of Springs on cross pieces 6 and 7,respectively. The latter may form part of some other machine, or may besupported in any preferred manner, depending on the circumstances. Asshown, two heavy sill pieces of 2x6 are set on edge and the lower crosspieces 7 fits. in a mortise about a foot from the right end. At the leftthe cross piece 6 is supported by two uprights, one of which lisindicated by reference Character 10, at such a height that the screenwill be inclined at an ang-le of about 80 from the horizontal.

The Springs which support the cross pieces 4 and 5 are four in' numberand are indicated by reference characters 11 to 14, inclusive. TheseSprings and associated parts are all alike. v Considering spring 14 andits mounting more in detail, the centering bolt 15 fits tightly in ahole bored in cross piece 7 and is held firmly in place by nuts aboveand below. A large steel disc or washer 16 is placed on the centeringbolt before the upper nut is screwed down. This washer forms a bearingsurface for the spring 14,

the lower coil of which fits tightly around.

the upper nut. The upper coil of the spring fits loosely around thecentering bolt 15 and supports one end of the cross piece 5, there beinga second washer 17 interposed between the spring and cross piece. Thissecond washer is drilled with small holesv and is` secured to the crosspiece '5 with screws.

The centering bolt 15 passes up through a central hole in the washer andcross piece,

the hole being large enough to insure 'a loose fit. The upper end of thespring may, or may not beattached to washer 17. 'If the former, the endof the spring is bent up `at right 'angles and extend' into a holedrilled in the washer to receive it. As stated before, the other threeSprings and associated parts are like the one described. These Springsevidently constitute a looseor flexible support for the frame of thescreen, on.

which it is free to vibrate.

The means for causing the screen to vibrate lwill next be considered.This comprises a heavy shaft 20, supported in bearings 21 and 22, whichare attached to the frame of the screen. The shaft is preferably mountedsome-what to the left of the center of the screen and at this point the-side pieces 2 and 3 are strengthened by ladjusted by means of the outernuts, and if desired a heavier weight can be substituted for clip 29.The U bolt 26 is similar to the one described and may be on the sameside of the shaft, as shown in the drawing, or on the' opposite side, asvwill be vexplained prese-ntly.

Power is supplied to the pu'lley wheel 30 by means of a suitable belt 31which may be driven by the pulley wheel 32. The latter wheel is drivenby any desired sourceof power, as for example, a small electric motor.

In order to hold the screen in position against the tension of the'belt, two loose or flexible connections are provided at` the upper endoffthe screen. These consist lof two i. shaped bars of iron 34 and 35which are bolted to the cross piece' 6, and two similiar 11. shaped bars36 land 37 which are bolted to the' cross piece 4, together with thebolts 38 'and 39 by means of which the corresp/onding bars areconnected. 'It isv noted that the holes` through which bolts 38 and 39pass are large enough to make a loose ifit, so 'that the attachmentswill not interfere with the vibrations of the screen.

The materialmay be vfed to the screen in any desired manner, many waysbeing well known. Undercertain circumstances some type of beltconveyormay be used. I have shown, however, a hopper indicated by referencecharacter 40, which is suitably supported so that the opening at thebottom is about two inches above the surface of the screen. The hopperis preferably provided with a vertically movable gate at 41 in order Ithat the width of the opening may be adjusted. 'f

Hav'i'ng explained the construction of my improved screen, I will nowdescribe its operation briefiy. Assume that the hopper i 40 is filledwith gravel or crushed rock, or any other material that is' to be runthrough the screen. lVhen the material, gravel for instance, is dumpedinto |the hopper it/will run through' the opening at the bottom of thehopper and form a hill or ridge extending across the screen the fullwidth of the hopper. Some of the' finei' particles of course fallthrough the screen but the openings are soon plugged by larger pieces ofmaterial and a stable condition is reached almost at once. The power isnow switched on. As the shaft speeds up it begins to vibrate, and atfull speed, about` 1800 R. P. M., a. steady high frequency vibration issecured. The motion of the shaft is communicated to the screen and as amatter of fact the shaft and screen vibrate in unison and as a singleunit. The'vibrations have an immediate effect on the material which hasflowed through the hopper. The fine particles pass through the screen ina steady stream, while the larger pieces descend on the surface of thescreen and pass' over the end. Fresh material ,of course runs down fromthe hopper as fast as that below is displaced.

It is not to be understood that the screen is shaken violently up anddown during these Operations. On the contrary, the up and down motion isslight, being scarccly perceptible to the eye, and is accompanied y`byahumming sound of a pitch corresponding to the frequency of thevibrations. As

stated, the amplitude of the vibrations is extremely small, and islargely independent of the size of the weights, which are much too lightto cause forced vibrations of the screen. As a matter of fact the screenis operative if the weights are entirely omitted, since any heavy shafthas a'tendency to vibrate' when rotated at high speed. The combinationof the spring supported screen and the heavyv shaft, however, have acertain natural period of vibration and the weights are useful inadjusting this period to the frequency of the power source. this purposethey may be set on the shaft at different angles to each other, or theout- For side clips may be moved relative to the shaft.

' It will be seen that I have devised novel and effective means forvibrating a. screen of the type described, comprising an unbalancedshaft mounted on the frame of the screen, whereby the vibrations of theshaft may be transmitted direct to the screen without interveningmechanism. VVhile have shown and described a certain specific embodiment'of my invention, it is possible to apply the principles involved tomany types of screens and similar devices, and fin different ways; andldo not therefo-re wish to be held strictly to the precise form gles tothe plane of said belt.

of my invention which is shown herein, but desire rather to secure andhave protected by Letters Patent all modifications of my invention whichcome fairly within the scope of the app'ended claims. IVhat I claim is:

l. In a vibrating screen, a frame supported on Springs, a' vibratingdevice comprising a shart supported on said frame, a belt for drivingSaid shaft, and holding means at one end of said screen independent ofthe supporting springs for takmg the pull of the said belt, the saidbelt and holding means constitut-ing means for limiting the` vibrationsof said Screen to a plane at right an- 2. In a vibrating screen, a framesupported on Springs, a vibrating device comprising a Shaft supported onsaid frame, a belt for driving said shaft, and a pair of holding devicesat one end of Said screen for holding the same in position against thepull of the said belt, the said belt and holding'devices constitutingmeans for preventing said screen from vibrating horizontally whilepermitting the same to vibrate freely up ,and down.

3. In a vibrating screen, a frame, a vibrating device comprising a shaftsupported on said frame, a belt for driving the said sha-ft, a pluralityof compression coil Springs beneath the said frame to support the weightthereof, the Said frame resting loosely on said Springs, and retainingmeans for holding the screen in position against the 'pull'o-f the saidbelt.

4. In a vibrating screen. a frame, a vibrating device comprising a shaftsupported on said frame, a belt for driving the said shaft, a pluralityof compression coil Springs beneath the said frame to support the weightthereof, the said frame resting loosely on said Springs, independentmeans for holding the :screen against the pull of said belt, and

loose fitting positioning means associated with each spring forretaining said screen in approximate position.

5. In a vibrating screen, a frame, Springs at opposite ends of saidframe supporting it at an angle from the horizontal, an unbalthe screenwhile at the lower end the vibrations are unrestricted.

6. In a vibrating screen, a frame, a vibrating device comprising a shaftsupported on said frame, a substantially horizontal belt for drivingsaid shaft, retaining means at one endl of said screen for holding thesame in position against the 'pull of the belt, the

.arranged to permit said frame to vibrate freely up anddown.

7. In a vibrating Screen, a frame, a' vibrating device comprising anunbalanced shaft supported on said frame, a driving belt and suitableholding devices pulling in opposite directions on said frame, wherebylongitudinal movement of the frame is substantially prevented, and aplurality of compression ccil Springs upon which the said frame isloosely supported, whereby it is adapted to vibrate freely up 'and down.

8. In a vibrating Screen, an inclined frame, a vibrating devicecomprising .a transverse rotatable shaft supported in bearings on saidframe, weights on said shaft to unbalance the same in order to Set upvibrations in the screen When the shaft is rotated, and means forretaining said screen in position arranged to permit the same to vibratefreely up and down whileopposing vibrations in the plane of the screen,said means including Springs of the compression type offering aresilient action only to vibrations in a plane perpendicular to' theplane of the Screen.

9. In a vibrating screen, an inclined frame,

a vibrating device comprising a transverse rotatableshaft supported inbearings on said frame, weights on said shaft-to unbalance the same inorder to cause the screen to Vibrate when the shaft is rotated, meansfor suppressing vibrations inthe plane of the screen, and means forsupporting the weight of the screen comprising compression Springsacting in a plane perpendicular to the plane vof the screen, therebypermitting the screen to vibrate freely up and down.

'Signed at Chicago, county of Cooka and State of Illinois, this ninthday of October, 1920.

JOSE-PH J.

